Wireless devices for communication such as terminals are also known as e.g. User Equipments (UE), mobile terminals, wireless terminals and/or mobile stations. Terminals are enabled to communicate wirelessly in a cellular communications network or wireless communication system, sometimes also referred to as a cellular radio system or cellular networks. The communication may be performed e.g. between two terminals, between a terminal and a regular telephone and/or between a terminal and a server via a Radio Access Network (RAN) and possibly one or more core networks (CNs), comprised within the cellular communications network.
Terminals may further be referred to as mobile telephones, cellular telephones, laptops, or surf plates with wireless capability, just to mention some further examples. The terminals in the present context may be, for example, portable, pocket-storable, hand-held, computer-comprised, or vehicle-mounted mobile devices, enabled to communicate voice and/or data, via the RAN, with another entity, such as another terminal or a server.
The cellular communications network covers a geographical area which is divided into cell areas, wherein each cell area being served by a base station, e.g. a Radio Base Station (RBS), which sometimes may be referred to as e.g. “eNB”, “eNodeB”, “NodeB”, “B node”, Base Transceiver Station (BTS), or AP (Access Point) or radio AP, depending on the technology and terminology used. The base stations may be of different classes such as e.g. macro eNodeB, home eNodeB or pico base station, based on transmission power and thereby also cell size. A cell is the geographical area where radio coverage is provided by the base station at a base station site. One base station, situated on the base station site, may serve one or several cells. Further, each base station may support one or several communication technologies. The APs or base stations communicate over the air interface operating on radio frequencies with the terminals within range of the APs or base stations. In the context of this disclosure, the expression Downlink (DL) is used for the transmission path from the radio AP to the wireless terminal. The expression Uplink (UL) is used for the transmission path in the opposite direction i.e. from the wireless terminal to the radio AP.
Superdense networks (SDNs) are extremely dense deployments of radio access points (radio APs) for wireless communication with inter-site distances in the order of, or even less than, tens of meters. With such a dense deployment the number of simultaneously active wireless terminals per radio AP is expected to be low. Therefore, SDNs are assumed to be noise-limited as opposed to traditional cellular networks which are typically interference-limited in scenarios with high traffic density. Noise-limitation is a desired property since it enables high link bit rate and simplifies radio resource management, coordination, and possibly also radio receiver implementations. SDNs are sometimes also referred to as ultradense networks. (UDNs).